A couple of mornings ago, it was 50F outside. The #2 truck has been
outside all night and everything about it was cold soaked. So I fired
up the Hotstart heater. The air temp through the vents or the
defroster went from 50F to 100F in about 2 minutes. I only had the
radio clock to judge by. From 100F and higher it warmed up more
slowly. I’ll use a timer and wait for colder weather for another test.
This time the Hotstart did not open the circuit due to hitting the
over temp threshold.

A 50 degree delta in 2 minutes is a great improvement in heater
performance versus stock. At least it feels that way. I will also get
the data from the #1 truck’s heater so they can be compared side by side.